This invention relates generally to mounting assemblies for night vision devices, and more particularly to a flip-up helmet mount for night vision devices that includes an adjustable socket assembly for mounting the goggles to the helmet mount, a break away latch assembly, automatic shutdown assemblies, position adjustment, tilt adjustment, focal adjustment, vertical adjustment, and a locking mechanism, wherein the adjustment mechanisms are designed to allow for one-handed operation by the user of the night vision device.
Night vision devices are commonly used by military personnel for conducting operations in low light or night conditions. The night vision devices utilized by the military typically include image intensifier tubes and associated optics that convert infrared and near infrared light into viewable images. A common night vision device currently being used in the U.S. Army is the PVS7 night vision device, manufactured by ITT Corporation in Roanoke, Va.
Assemblies for mounting night vision devices to a helmet are well known in the art. These mounting assemblies allow a user""s hands to remain free while viewing a scene through the night vision device. Prior art mounting assemblies typically include one or more of the following features: positional adjustment of the night vision device between a use and stowed position; tilt angle adjustment of the night vision device relative to the user""s eyes; focal adjustment of the location of the night vision device relative to the user""s eyes; and automatic shutdown of the night vision device when not in the use position.
A known mounting assembly for night vision devices encompasses a flip-up helmet mount that attempts to provide all of the features identified above. However, that device is believed to be deficient in its operational aspects because, among other reasons, the flip-up helmet mount is not designed for one-handed operation. More particularly, the tilt adjustment means disclosed requires a user to loosen a locking knob with one hand, while at the same time repositioning the night vision device with the other hand. Obviously, given the conditions under which night vision devices are typically used, it is undesirable and potentially unsafe for adjustment of the night vision device to occupy both hands of the operator. If both hands of the operator are required to adjust the night vision device, then the operator will be unable to continue carrying a weapon or other equipment in one of his hands. It can certainly be appreciated that having to put down one""s weapon in order to adjust the night vision device may expose the operator of the night vision device to certain unnecessary risks.
Known flip-up helmet mounts are also deficient in operational aspects because of jamming susceptibility of the automatic shutdown assembly. The automatic shutdown assembly includes a magnet housing having an S-shape or question-mark shape. A combination of an S-shaped cavity for movement of a relatively long, narrow bar magnet within results in an automatic shutdown assembly with questionable reliability. Specifically, the long, narrow bar magnet can easily become askew within the S-shaped cavity as the magnet moves within the cavity. When the magnet becomes askew within the cavity, the automatic shutdown assembly becomes jammed and the night vision device does not automatically turn off when rotated into the stowed position. This is obviously undesirable since the phosphor yellow/green light emitted from the night vision device would then be visible to possibly hostile personnel in front of the operator.
Known flip-up helmet mounts are inadequate for the conditions in which the night vision devices are typically used. For example, when the helmet mount is moved from one position to another, the magnet in the automatic shutdown assembly produces a significant amount of noise upon contacting the end of the cavity. Obviously, excessive noise can draw unwanted attention to the operator of the night vision device. It is also important that the automatic shutdown assembly not intermittently turn the goggles off in use or on while not in use due to inadvertent movement of the magnet caused by movement of a person wearing the goggles. In another known flip-up helmet mount, a significant amount of noise is produced by a rib that is received into one of two grooves for retaining the night vision device in either the use or the stowed position.
Further, the focal adjustment assembly of the known mount requires the operator of the night vision device to apply force inwardly to a pair of release buttons in order to adjust the location of the night vision device relative to his eyes. It is believed that this requires a rather awkward movement of the hand or hands of the operator that makes focal adjustment relatively difficult. In addition, the known helmet mounts fail to provide a simple means for adjusting the vertical position of the night vision device relative to the user""s eyes. The performance of the night vision device is diminished if the user is unable to vertically align the device in a position in front of the eyes that enables a complete and steady view through the goggles.
Night vision devices and helmet mounts are often manufactured by different manufacturers. So that the parts will fit together, they are manufactured to certain specifications but having dimension variations of up to {fraction (10/1000)}xe2x80x3. The fit of the goggles into the helmet mount chassis is difficult with such variances. The fit should not be too loose, as noise emitting from jiggling contact between the goggles and the chassis (for instance, when the user is in motion) should be avoided. Moreover, jiggling of the goggles in the mount makes it more difficult to see clearly through the goggles. Yet, the fit of the goggles should not be so tight that it is difficult for the goggles to be connected with the helmet mount, or disconnected therefrom. A snug fit of the goggles into the helmet mount is desired with a minimum amount of force required to insert the goggles into the helmet mount. Moreover, it would be desirable to prevent the night vision device from being damaged if a certain force, such as an impact by a tree branch, is applied to the night vision device. A means for allowing the connection between the helmet mount and the night vision device to be disconnected when a certain force is encountered would prevent such unnecessary damage.
An additional problem encountered with current helmet mounts is the night vision device unintentionally moving from the stowed or in use position. For example, if the user has the night vision device in the stowed position it could be dangerous for the device to be inadvertently bumped or jolted into the use position. Accordingly, it would be desirable to have a locking mechanism that retains the night vision device in either the stowed or in use position until certain deliberate actions are taken by the user.
These and other problems exist with the flip-up helmet mounts for night vision devices disclosed in the prior art. Consequently, a need exists for an improved flip-up helmet mount.
The present invention, therefore, provides an improved flip-up helmet mount for night vision devices. More particularly, the flip-up helmet mount according to the present invention is designed to allow for a substantially quiet automatic shut-off night vision device that operates only when intended, and to allow for a snug fit of night vision devices into the helmet mount. In addition, the flip-up helmet mount is designed to allow for one-handed adjustment of the position, tilt, and focus of the night vision device.
The flip-up helmet mount includes a helmet block for securing the night vision device to a helmet, and a chassis for receiving the night vision device. The chassis is rotationally coupled to the helmet block by a bracket member extending between the helmet block and the chassis.
In a presently preferred embodiment, a goggle horn of the night vision device is secured into an adjustable socket assembly having an upper socket and a lower socket coupled to the upper socket. The lower and upper sockets have a goggle horn receiving area that substantially corresponds to the wedge-shaped goggle horn. However, the goggle horn receiving area is dimensioned to be slightly smaller than the smallest possible horn given the allowed tolerances.
Preferably, lower socket is capable of moving {fraction (20/1000)}xe2x80x3 in a direction away from the upper socket while still being coupled thereto. Screws that provide the connection between the upper and lower sockets are placed through smooth holes in the lower socket, the holes with a counterbore spaced from the head of the screws, and connected to threaded holes in the upper socket. A spring is provided around each screw in the lower socket that biases the lower socket toward the upper socket. However, the counterbore allows the lower socket to be moved away from the upper socket against the spring force. Because the screws have a threaded connection to the upper socket, the upper socket and the screws maintain their positions relative to one another. As a result, the upper socket and the lower socket may separate while accommodating a goggle horn into the goggle horn receiving area.
The goggle horn slides over a detent in the goggle horn receiving area until the detent is received into an aperture in the goggle horn. When the detent is received into the goggle horn, the spring is biased to the original position thereby pulling the lower socket closer to the upper socket. Because of the dimensions of the goggle horn receiving area, a horn will always be under spring pressure while in the receiving area with the upper and lower sockets spread at least some distance apart. In an alternative preferred embodiment, the lower socket has a break away latch assembly instead of the fixed detent, which allows the goggle horn to be removed from the socket assembly when a certain force is applied to the night vision device. The break away latch assembly makes use of at least one spring that pushes against a latch that is pivotally secured in the lower socket.
A position adjustment assembly is provided within the helmet block for adjusting the night vision device between a use position, in front of the user""s eyes, and a stowed position, out of the line-of-sight of the user. The flip-up helmet device includes an automatic shutdown assembly for automatically shutting down the night vision device when it is not in the use position. Further, in a presently preferred embodiment, the automatic shutdown assembly includes a magnet module having a vertically extending cavity with a substantially oval-shaped profile. A cylindrical bar magnet is slidably received within the cavity to move in response to movement of the night vision device between the use and stowed position. The automatic shutdown assembly automatically shuts down the night vision device whenever it is not in the use position. The shape of the cavity and the dimensions of the bar magnet combine to produce a reliable automatic shutdown assembly that is essentially jam proof. Placed in the cavity with the magnet is a damping fluid that has sufficient viscosity to slow the velocity of the magnet when the positions are being changed, so that noise emitted from contact of the magnet with the cavity sides is substantially eliminated. The fluid also reduces the possibility of inadvertent operation.
In a presently preferred embodiment, the position adjustment assembly includes a spring-biased ball and detent system, wherein a plurality of balls are biased by springs toward a shaft, rotationally received in a transverse bore in the helmet block, that includes a pair of transverse detents extending along the length of the shaft, corresponding to the use and stowed position of the night vision device. The spring-biased ball and detent system provides for extremely quiet operation of the flip-up helmet mount.
A tilt adjustment assembly is additionally provided for adjusting the tilt angle of the chassis relative to the bracket member, and thus the night vision device relative to the user""s eyes. The tilt adjustment assembly includes a cam system, wherein rotation of a cam knob produces rotation of the chassis relative to the bracket member. The cam based tilt adjustment assembly provides for one-handed adjustment of the tilt angle of the night vision device. Moreover, the cam based assembly permits substantially infinite adjustment of the tilt angle within a predetermined range.
Additionally, in a presently preferred embodiment, a focal adjustment assembly is provided for adjusting the location of the night vision device relative to the chassis. The focal adjustment assembly includes a hinged release lever that is biased by a return spring to engage one of a plurality of notches on one of a pair of racks of the chassis. The night vision device is slidably received on the racks of the chassis. Application of a downward force on the release lever disengages the release lever from the notch and permits adjustment of the location of the night vision device relative to the chassis. The single release-lever provides for one-handed adjustment of the location of the night vision device and is believed to be ergonomically superior to prior art systems.
Vertical adjustment of the night vision device relative to the user""s eyes is also provided for in a presently preferred embodiment. A rack/pin system achieves vertical movement of the chassis by moving a front plate that is slidably coupled to a back plate, wherein the chassis is adjustably coupled to the front plate. Additionally, a pin system is provided that uses a spring actuated button and gripping means to move up and down within a plurality of grooves that are machined into the back plate. Alternatively, vertical movement of the night vision device can be achieved by a gear drive system. The gear drive system moves the chassis up and down by rotational movement of a lever mounted to the front plate which is fixedly connected by a shaft to a gear disposed within a housing in the back plate, wherein rotation of the lever rotates the gear, thus causing the gear to move within the gear housing.
Additionally, a locking mechanism is provided in an alternative preferred embodiment which allows the night vision device to be moved from the stowed position to the use position, or vice versa, by compressing an activation button protruding from the helmet block. When the activation button is compressed, a shaft that is integrally connected to the activation button and disposed within the helmet block is pressed against a spring. The spring is mounted between the shaft and the helmet block, and when compressed a lock that is pressing against the shaft changes position, thereby disengaging the locking mechanism. A pivot sleeve is also disposed in the helmet block that is engaged by a side of the lock that is opposite the side pressing against the shaft, and when the activation button is compressed the pivot sleeve is able to rotate, thus allowing the position of the night vision device to be changed by the user.